Three Oakland police officers were killed and one is currently on life support after two shootings Saturday, the first after a routine traffic stop and the second after a massive manhunt ended in gunfire, authorities said. The gunman, who was wanted on a parole violation, was also killed.

The violence on Saturday began when two officers on motorcycles stopped a 1995 Buick sedan in east Oakland just after 1 p.m., Oakland police spokesman Jeff Thomason said. The driver opened fire, killing one officer and gravely wounding another.

"It's in these moments that words are extraordinarily inadequate," said Mayor Ron Dellums at a somber news conference announcing the slayings. It was the first time in the history of the Oakland Police Department that three officers were killed in the line of duty in the same day.

The gunman then fled on foot, police said, leading to an intense manhunt by dozens of Oakland police, California Highway Patrol officers and Alameda County sheriff deputies. Streets were roped off and an entire area of east Oakland closed to traffic.

Around 3:30 p.m. officers got an anonymous tip that the gunman was inside a nearby apartment building. A SWAT team entered an apartment to clear and search it when the gunman opened fire, police said. Two members of the SWAT team were killed and a third was grazed by a bullet, police said.

The slain officers were identified as Sgt. Mark Dunakin, 40, who was killed at the first shooting. The officers killed at the second location were Sgt. Ervin Romans, 43, and Sgt. Daniel Sakai, 35.

Oakland police retracted a statement they released earlier Sunday that a fourth officer shot had died. Spokesman Jeff Thomason said 41-year-old Officer John Hege was pronounced brain dead but was still on life support Sunday afternoon.

Thomason said that a final decision was still being made about donating Hege's organs.

Hege's father, Dr. John S. Hege, a retired physician from neighboring Piedmont, said his son loved being a policeman. He worked well with people and was an Eagle Scout. He played high school football and wrestled. He umpired and coached even as a youth, and joined the Oakland Police Department reserves.

As for the slain shooting suspect, the father said, "The man was evidently terribly desperate. It is a sad story..."

Grieving officers at the police station hugged and consoled each other.

Gov. Arnold Schwarzenegger was to arrive in Oakland Sunday afternoon for a private meeting with Dellums and police.

"All four officers dedicated their lives to public safety and selflessly worked to protect the people of Oakland," Schwarzenegger said in a statement released Saturday. "Our thoughts and prayers are with the families of those lost, the Oakland Police Department and law enforcement officers throughout California during this difficult time."

Police said Mixon wielded two different weapons. One gun was used at the first scene and an assault rifle was used at the apartment building where he was hiding.

"[Mixon] was on parole and he had a warrant out for his arrest for violating that parole. And he was on parole for assault with a deadly weapon," said Oakland police Deputy Chief Jeffery Israel.

Police said they did not know why the officers initially stopped the suspect, but said it apparently was a routine traffic stop. Thomason said Mixon had an "extensive criminal history" and was wanted on a no-bail warrant.

Mixon's family gathered Sunday at his grandmother's East Oakland home, where he had stayed on and off since being released from a nine-month sentence for a parole violation, family members said.

He had previously served six years in state prison for assault with a firearm during an armed robbery in San Francisco, the family said. While he was in Corcoran state prison, he married his childhood girlfriend, they said.

Mixon's uncle, 38-year-old Curtis Mixon of Fremont, said his nephew had become depressed because he could not find work as a convicted felon. His nephew expected authorities to issue an arrest warrant for missing parole meetings, even though the he felt he was not to blame, he said.

"I think his frustration was building up, but he was trying to better himself," Curtis Mixon said.

People lingered at the scene of the first shooting. About 20 bystanders taunted police.

Tension between police and the community has risen steadily since the fatal shooting of unarmed 22-year-old Oscar Grant by a transit police officer at an Oakland train station on Jan. 1.

That former Bay Area Rapid Transit officer, Johannes Mehserle, has pleaded not guilty to a murder charge. A preliminary hearing is scheduled for Monday. Violent protests erupted on the streets of Oakland in the weeks after Grant's death, further inflaming tensions.

Officer deaths are nothing new in Oakland. The memorial wall in the Oakland Police headquarters shows that at least 47 officers died before Saturday. The wall shows the last officer killed in Oakland was in January of 1999.

People left four bouquets of white roses under the granite wall inside the building lobby.